Burglar-alarm



UNITED STATES PATENT Fries.

JOHN F. HARVEY, OF J OHNSONBURG, AND DAVID SHIELDS, OF ERIE, ASSIGNORS TO MATTHEW GRISWOLD, OF ERIE, PENNSYLVANIA.

BURG'LAR-ALARM.

SPECIFICATION forming part of Letters Patent No. 515,677, dated February 27, 1894.

Application filed March 1, 1893.

To 095? whom it may concern:

be it known that we, JOHN F. HARVEY, residing at Johnsonburg, in the county of Elk, and DAVID SHIELDS, residing at Erie, in the county of Erie, State of Pennsylvania, citizensof the United States, have jointly invented certain new and useful Improvementsin Burglar-Alarms; and we do hereby declare the following to be a full, clear, and exact descriptlon of the invention, such as will enable others skllled in the art to which it appertains to make and use. the same, reference being bad to the accompanying drawings, and to the letters of reference marked thereon, forming part of this specification.

Our 1nvention consists in the improvements in portable burglar alarms hereinafter set forth and explained and illustrated in the accompanying drawings in which- Figure 1. shows a view in elevation of our improved portable burglar alarm in place on the caslng of a door. Fig. 2. is a rear view in elevation of the same. Fig. 3. is a side view of same with one side of the frame removed therefrom.

The object of our invention is to construct a portable burglar alarm which can be quickly attached to a door casing in such a manner that the opening of the door will cause it to explode a blank cartridge placed therein.

In the construction of our improved portable burglar alarm shown in the drawings, A, A constitute the frame work thereof, these parts being riveted together as hereinafter set forth. This frame is provided at its base B with a pointed screw 0 adapted to be screwed into a door casing D for securing it in place thereon, and in the upper end E of the frame we make an opening F adapted to receive a blank cartridge G. This frame A, A is made with a lateral curve therein, so that when the base B thereof is in place on a door casing D, the upper end of the frame wlll project laterally, so as to be substantially in line with the edge of the door H when closed.

In the base B of the frame A, A we pivot an arm I, which is provided with a curved thrust spring J, one end e of which is seated 1n a notch f in the upper end E of the frame, and the other end at thereof in a notch h in the pivoted end of the arm I; this notch it being so located eccentrically to the pivot or derial No. 464,279. (No model.)

axis L upon which the arm I moves that when the arm I is thrown back as illustrated in Figs. 1 and 3; the end cl of the spring J is slightly beyond the center of the axis L, so that the tension of the spring J tends to hold the arm I in an open or extended position, as illustrated in Figs. 1 and 3, but when the arm I is moved slightly forward from that position, the spring J instantly operates on the eccentric notch h therein to close the arm I with a forcible blow against the upper end E of the frame in which it is mounted, so as to bring the projection 19 on the up per end of the arm I against a cartridge G placed in the opening F in the frame with sufficient force to explode it.

The parts A, A of the frame, the springJ and the arm I are all secured together by means of the rivets a and L, the rivet L being the axis upon which the arm I moves as hereinbefore described.

Having thus fully described our invention, its operation is so obvious that further description thereof is deemed unnecessary; therefore, what we claim as new, and desire to secure by Letters Patent of the United States, is

The combination in a portable burglar alarm, of a laterally curved frame having a central longitudinal recess therein, apointed screw at the base of said frame adapted to be screwed into a door casing, and a transverse opening adapted to receive a blank cartridge in the upper end of said frame, with an arm I pivoted in the base of the recess in said frame and a rivet L and having a notch h located therein eccentrically to the rivet L, and a curved thrust spring J, one end of which enters a notch in the upper end of said frame, and the other the eccentric notch h in said pivoted arm, whereby the spring J operates tangentially to the rivet'L with a constant tension upon said lever, not only in one direction to hold it open, but also in the opposite direction both during its traverse in striking the cartridge and afterward, substantially as set forth.

In testimony whereof we affix our signatures in presence of two witnesses.

JOHN F. HARVEY. DAVID SHIELDS. Witnesses:

MATTHEW GRIsWoLD, Jr., F. EINFELDT. 

